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A277973 Sum of horizontal positions of the first peak in all bargraphs of semiperimeter n. 1
0, 0, 0, 1, 6, 25, 91, 311, 1029, 3346, 10778, 34544, 110444, 352785, 1126885, 3601617, 11521648, 36899528, 118322448, 379908707, 1221423149, 3932113059, 12675055399, 40909511880, 132200481507, 427718677728, 1385419058692, 4492446685542, 14582927712740, 47385785436719 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

COMMENTS

Horizontal position is x-coordinate of the start of the leftmost horizontal step of the first peak.

LINKS

Table of n, a(n) for n=1..30.

A. Blecher, C. Brennan, and A. Knopfmacher, Peaks in bargraphs, Trans. Royal Soc. South Africa, 71, No. 1, 2016, 97-103.

FORMULA

G.f.: (2*x^3*(x^2-sqrt(x^4+2*x^2-4*x+1)+1)) / ((1-x)*(-x^2+sqrt(x^4+2*x^2-4*x+1)-2*x+1)^2).

EXAMPLE

For n = 4, a(4) = 1, as only the bargraph with first column of height one and second column of height two has horizontal position 1, all other cases are zero.

CROSSREFS

Cf. A271941, A273720, A273345.

Sequence in context: A001871 A000392 A099948 * A143815 A209241 A092491

Adjacent sequences:  A277970 A277971 A277972 * A277974 A277975 A277976

KEYWORD

nonn

AUTHOR

Arnold Knopfmacher, Nov 07 2016

STATUS

approved

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Last modified June 18 14:52 EDT 2019. Contains 324213 sequences. (Running on oeis4.)